|Publication number||US7485101 B1|
|Application number||US 10/891,427|
|Publication date||Feb 3, 2009|
|Filing date||Jul 15, 2004|
|Priority date||Mar 22, 2002|
|Publication number||10891427, 891427, US 7485101 B1, US 7485101B1, US-B1-7485101, US7485101 B1, US7485101B1|
|Inventors||Yousry B. Faragalla|
|Original Assignee||Faragalla Yousry B|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (17), Non-Patent Citations (4), Referenced by (2), Classifications (12), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present application is a continuation-in-part application of application Ser. No. 10/102,640 filed Mar. 22, 2002, now U.S. Pat. No. 6,780,161 entitled APPARATUS FOR EXTRACORPOREAL SHOCKWAVE LITHOTRIPTER USING AT LEAST TWO SHOCKWAVE PULSES, the priority of which is claimed.
The invention relates to a torso positioning and imaging apparatus for improving the efficiency of shockwave treatment in a living body or tissue while, at the same time, reducing the harmful effects of such treatment and to a method of treating a living body or tissue with such an apparatus.
In the past two decades, fragmentation of concretions inside a living body by focused shockwaves from outside the body was established as a method of treatment. Recent research is also developing for the application of shockwave treatment in the field of orthopedics and in pathological tissue ablation as well as in other different types of treatment.
The mechanisms by which focused shockwaves disintegrate stones in Extracorporeal Shock Wave Lithotripsy are still not well understood. However, several mechanisms for stone fragmentation have been proposed and documented in the literature.
The shockwave pulse is comprised of a positive peak pressure up to about 120 MPa, which lasts for up to about 2 microseconds followed by negative peak pressure up to about 20 MPa with about 2 to 8 microseconds duration.
It is further known in the art that the negative pressure induces transient cavitation bubbles around the focal point. Ensuing pulses cause these cavitation bubbles to collapse. When bubbles collapse adjacent to a solid surface like a stone, it will take place asymmetrically leading to the formation of high speed, liquid micro jets that hit the stone surface and cause cracking and fragmentation. Only a percentage of these micro jets is directed to the stone while the remaining part is consumed by the adjacent tissues leading to tissue damage.
It is also mentioned in the literature that the conditions required for fracturing stones include one or more of the following: compression and release, tension or spall and cavitation induced stress. Fragmentation involves separation of crystal layers and fracture and cleavage of crystals. The disintegration of stones occurs by the progressive initiation of cracks and their stepwise extension through the material. Brittle materials fail under compressive shock loading by initiation and growth of micro cracks from internal defects such as pores or inclusion or from material boundaries such as interfaces with organic or fibrous material or grain boundaries.
With repeated pulses the micro cracks grow on a prospective spall plane and they coalesce on reaching a critical length creating a fragment. Under pressure, the micro cracks grow in the axial plane; i.e. the failure is in the direction of maximum applied compression that is the direction of shockwave propagation. On the other hand, under tension, micro cracks grow on a plane perpendicular to the direction of applied tension; i.e. perpendicular to the direction of the shockwave propagation.
In our above-identified application, we disclose that the collapse of the cavitation bubbles can be controlled by the sequential timing and direction of additional shockwaves. Hence, the use of one or more other shockwave sources to generate another shockwave propagating at an appropriate angle from the direction of propagation of the primary shockwave will enhance the treatment effect of shockwaves and abolish or minimize the tissue damage outside the focal area. The value of the angle between these shockwave sources varies according to various factors such as the type of treatment and the level of energy. The timing of generation of shockwaves from these sources could be instantaneous or with a delay period between each of about 1 millisecond up to about 100 milliseconds. This delay varies according to various factors such as the type of treatment and level of energy. The present invention provides a unique support table and medical imaging apparatus, e.g. MRI, x-ray, ultrasound, etc., to facilitate and enhance targeting.
The above and other objects, advantages and features of the invention will become more apparent when considered with the following specification and accompanying drawings wherein:
A preferred embodiment of the present invention comprises the usage of a unique support table 20, x-ray imaging apparatus 30 and ultrasound imaging apparatus 31, 32 and two shockwave sources 10 and 11 where said shockwaves are reaching a focal point or area F2 (which has been located by the medical imaging apparatus, discussed later herein), each from a different angle and the site where treatment is intended is mobilized to be in the focal area F2. Each shockwave source includes a shockwave generator operatively coupled to a reflector. The angle between the two shockwaves is variable, for example from about 67 degrees up to about 105 degrees according to the type of treatment and energy level. However, in a most preferred embodiment, this angle is set at about 90 degrees, i.e. the direction of the propagation of the two shockwaves are almost perpendicular to each other.
Controller CONT (
The timing of the generation of the two shockwaves is variable from instantaneous generation to a delay period between the two shockwaves up from about 1 millisecond to about 100 milliseconds. Yet, in the most preferred embodiment, this delay time is set at about 23 milliseconds. Also, according to other embodiments of the invention more than two sources of shockwaves may be involved regardless of the selected angles of directions of generated shockwaves and/or timing of their generation.
It is obvious to those skilled in the art that many modifications and/or alterations may be made within the description of this invention. Any prior art shockwave generator and reflector may be used in the present invention. In a preferred embodiment, Twinheads™, which was using two shockwave generators, has provided good results on experimental testing on in vitro stones. With an angle between axes of the two reflectors about 90 degrees and delay time of firing between the two sources about 23 milliseconds, the shockwave effects became more concentrated in the focal area with disappearance of any effects outside this focal area.
It was found that stone disintegration was limited to the focal area without propagation outside the area F2. Thus, with Twinheads™, damage to the surrounding tissues will be avoided or reduced because of the localization of shockwave effects in the localized focal area. Moreover, the quality of disintegration of stone was finer and more rapid, as it was the result of applying pressure and tension from two different directions to the stone, which enhanced the initiation of cracks and their extension throughout the stone.
Referring now to
While the invention has been described in relation to preferred embodiments of the invention, it will be appreciated that other embodiments, adaptations and modifications of the invention will be apparent to those skilled in the art.
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|Citing Patent||Filing date||Publication date||Applicant||Title|
|US20110263967 *||Oct 27, 2011||of higher education having a principal place of bussiness||Ultrasound based method and apparatus for stone detection and to facilitate clearance thereof|
|WO2013114366A1 *||Jan 31, 2013||Aug 8, 2013||Friedman, Itzhak||High pressure ballistic extracorporeal shockwave device, system and method of use|
|U.S. Classification||601/2, 601/3, 601/1, 600/437, 600/439|
|Cooperative Classification||A61B17/22004, A61B17/225, A61B17/2256|
|European Classification||A61B17/22B, A61B17/225P, A61B17/225|
|Sep 17, 2012||REMI||Maintenance fee reminder mailed|
|Sep 24, 2012||SULP||Surcharge for late payment|
|Sep 24, 2012||FPAY||Fee payment|
Year of fee payment: 4